In LTE-A (Long Term Evolution Advanced) R10 (Release 10), timing of multiple carriers makes reference to a timing advance (TA for short) value of a primary cell (PCell), that is, multiple carriers correspond to one TA value. However, in LTE-A R11 (Release 11), different carriers allow different TA values. Carriers may be grouped into different timing advance groups (TAG for short) according to different TA values. That is, TA values in one TAG are the same, and TA values in different TAGs are different.
Because TA values in different TAGs are different, for different carriers (that is, carriers in different TAGs), a case in which a portion of adjacent subframes overlap may occur, and a maximum overlap period is 30 μs. Furthermore, in a short overlap period, total transmit power of a user equipment (UE for short) may exceed maximum transmit power of the UE, causing that power is limited or that interference is limited because an interference level is reached.